The present invention relates generally to power monitoring systems and, more particularly, to automated alarm setpoint learning in an electrical meter for use in a power monitoring system.
Power monitoring (PMO) systems monitor the flow of electrical power in circuits through a plant or other facility. In the POWERLOGIC system manufactured by the instant assignee, Square D Company, circuit monitors and power meters are dedicated to power monitoring, while other compatible devices collect additional equipment information from protective relays, circuit breakers, transformer temperature controllers, and panelboards. Electrical data, such as current, power, energy, waveforms, and equipment status, is passed over a data network to one or more personal computers. The personal computers run power monitoring application software that retrieves, stores, organizes, and displays real-time circuit information in simple, usable formats. The information collected and stored in a power monitoring system helps operate a facility more efficiently. The quality of the data depends upon the accuracy of the instrumentation and the usability of the display formats.
The power meter can replace conventional metering devices such as ammeters, voltmeters, and watt-hour meters while providing other capabilities not offered by analog metering. The power meter""s true rms readings reflect non-linear circuit loading more accurately than conventional analog metering devices. The power meter calculates the neutral current, which can assist in identifying overloaded neutrals due to either unbalanced single phase loads or triplen harmonics. Circuits can be closely monitored for available capacity by keeping track of the peak average demand current.
Manual selection of appropriate magnitude and duration alarm setpoints for the numerous electrical parameters monitored by the CM4000 Circuit Monitor requires experience and expertise and can be time-consuming. This new system automates this process by collecting the needed data and applying a heuristic analysis to select appropriate setpoints.
Reliable Power Meters of Los Gatos, Calif. has a product called xe2x80x9cFull Disclosure Monitoringxe2x80x9d which approaches the issue of automating the alarming process by not selecting setpoints.
Briefly, in accordance with the foregoing, a circuit monitor for monitoring one or more metered values in an electrical circuit, including a system for selecting alarm setpoints based upon learned characteristics of normal operation of metered values, comprises a controller, a memory, the memory including a test register of alarms selected to be part of a learning process, the controller includes means for summarizing and characterizing the one or more metered values as histogram formatted data corresponding to metered values identified by a test register of alarms selected to be part is of a learning process, means for storing the histogram formatted data in the memory; means for organizing the stored data into a plurality of memory locations, each covering a fixed range of time duration; and means for selecting setpoints which produce a minimum product of metered value multiplied by time duration for Over Alarms, i.e., a metered value is above an upper limit setpoint, and a maximum product of metered value multiplied by time duration for Under Alarms, i.e., a metered value is below a lower limit setpoint.
In accordance with another aspect of the invention, a method of automated alarm setpoint learning in an electrical meter comprises summarizing and characterizing one or more metered values as histogram formatted data corresponding to metered values identified by a test register of alarms selected to be part of a learning process, storing said histogram formatted data in said memory, organizing said stored data into a plurality of memory locations, each covering a fixed range of time duration, and selecting setpoints which produce a minimum product of metered value multiplied by time duration for Over Alarms and a maximum product of metered value multiplied by time duration for Under Alarms.
In accordance with another aspect of the invention, a system for setting alarm points for metered values comprises means for summarizing and characterizing one or more metered values as histogram formatted data corresponding to metered values identified by a test register of alarms selected to be part of a learning process, means for storing said histogram formatted data in said memory, means for organizing said stored data into a plurality of memory locations, each covering a fixed range of time duration, and means for selecting setpoints which produce a minimum product of metered value multiplied by time duration for Over Alarms and a maximum product of metered value multiplied by time duration for Under Alarms.